Dark stool vs black stool the difference can be serious. Dark brown stool is often food or iron related. Black, tarry stool may indicate internal bleeding and needs urgent medical attention. Solved] ICD 10 CM and PCS codes. A 75 year old male was admitted to the hospital after coming to the emergency department Course Hero Symptoms of Melena and black stool causes: Here's when you should worry indications* for ordering a fecal occult blood test (FObT) Download Table